Nickel plating addities



United States Patent 3,160,574 NECKEL PLATING annrrrvns Jack L. Towie, leveland, and Henry R. Tuehewiezp This invention relates to electrodeposition of nickel and more specifically to eletroplating solutions adapted to produce semi-bright and in some cases fully bright electrodeposits of nickel.

The ability to obtain a semi-bright or bright deposit on a metal surface by the electrodeposi-tion of nickel is largely dependent on the type of organic additive employed in the nickel plating bath.

We have now discovered a new class of acid nickel plating solutions. These solutions contain compounds which will be referred to hereafter as 'levelers. The term leveler is applied because of the characteristic ability of the leveler compounds to improve smoothness and promote coverage of imperfections in the base metal. The leveler compounds may be described as alkyneoxya-lkaneamides and alkadiyneoxyalkaneamides. A general formula for these leveler compounds may be written as:

"ice

Compounds of the type set forth herein have been found to produce leveling when employed with an aqueous acid solution of nickel material capable of supplying nickel ions such as, for instance, the familiar all chloride, all sulfate, sulfate-chloride or Watts type, nickel fluo borate, nickel sulfamate types and combinations thereof.

In general, leveler compounds of the aforementioned type may be present in a plating bath in a range from .005 g./l. to 1.0 g./l. Within this broad concentration range there are three more limited ranges wherein the limits are determined by the type of cooperating additives employed with the leveler and by the type of nickel coating desired. When the leveler compound is employed alone in a nickel plating bath without the use of cooperating compounds, the leveler is preferably present in the range of from .005 g./1. to 0.1 g./l. When the leveler compound is employed in a nickel plating bath containing cooperating compounds for purposes of obtaining a semibright nickel plate, the leveler is preferably present in the range of from .01 g./l. to 0.3 g./l. When the leveler compound is employed in a nickel plating bath containing cooperating compounds for purposes of obtaining a bright nickel plate, the leveler is preferably present in the range of from .05 g./l. to 1.0 g./1.

Preferred concentration ranges for certain specific leveler RaCEC'( 2)nCRa compounds are given in the following table designated t, as Table I.

TABLE I Concentration Range Semi-bright Bright Leveler leveler+ 1eveler+ alone, cooperating cooperating g./1. compound, compound,

[1] HCEC-CHzOCHzOHgCONHg 3-(B-oxypropionarnide)propyne-L. .01-.04 A3110 .1-.5 [2] HCECCHz(OCHzGH2)3-CONH: 4,7,lo rioxa-m-yne-trldccanoic .005.02 .01.[)? .05. 25

ann e. [31NH2COOHZOHQOCHZCECCIIZOGH2CHZGONHZ lAbitswgrypropionamidw .01-. 04 .03'310 .1-.5

u yne- [4] NHZCO(CHRCHZO)ZCHQOECCH2 OCHZCH2 3CONHZ 1,4 bis-10,10-(4,7,10-rrioxa- .01-.04 .03. 10 1. 5

decanoic amide)butyne-2. [5] NHQCOCHzGHzOCHgCEC-CECOHzOGH GHQCONH: 1,6-bis(B-oxypropionamide) .025.1 .05.30 .25-.7

hexadiyne-Z.

(3H3 (3H3 [6] NHQCOCHOH2OCHQCEGCHZOGHQCHCONHQ l,4-bis(B-oxy-3-methylpropion- .01. 04 .03. 10 1. 5

amide)butyne-2. [7] HOCHZNHCOOH2OH1OCHgGECOHQQCH2OH2CONHCH2OH- 1,4-bis(N-hydroxymethyl-B- .O1.O6 .03. 20 .1-1.0

oxypropionamide)butyne-2. [8] CHsNHGOCHgCHgOCHzGEOCHgOCHzOHzCQNHCH: 1, l bis(N-methyl-B-oxypropion- .01.06 .O3. 20 .11.0

amide)butyne-2. I

wherein n is an integer from O to l inclusive, R is hydrogen or an alkyl group having from 1 to 11 carbon atoms, R is:

o l (OCHzCH-flr- NHZ CH3 0 ocH2oH2)w00H2( JHii-Nr[z wherein is an integer from 1 to 20, w is an integer from 0 to 20, Z is hydrogen, alkyl or hydroxymethyl, and K; may be hydrogen, hydroxymethyl, an alkyl group having from 1 to 11 carbon atoms,

wherein R and R are the same as previously defined.

Increased leveling and more uniform lustre are obtained with the leveler compounds of this invention when they are employed in combination with a second cooperating compound. The cooperating compound is defined as a tri-halo aldehyde or acetals or herniacetals of such aldehydes. Specific examples of such compounds are given in Table 11:

TABLE II 1, l-diethoxy-2,2,2-trichloroethane l-hydroxy-1-ethoxy-2,2,2-trichloroethane l,l-dimethoxy-2,2,2-trichloroethane l-hydroxy-1-methoxy-2,2,2-trichloroethane 1,1-dimethoxy-2,2,Z-tribromoethane l-hydroxy-1-ethoXy-2,2,2-tribrornoethane Trichloroethanal Tribromoethanal In general, the compounds of Table 11 When present in semi-bright plating solutions are employed in concentrations of .01 to 2.0 grams per liter. The preferred cooperating addition agent is trichloroethanal, which is present in the semi-bright plating solution in concentration of .01 to 0.5 gram per liter, and preferably from .03 to 0.1 gram per liter. 7

Constituents of the plating solution according to the preferred practice of this invention are:

(1) Water (2) A source of nickel ions selected from the group consisting of:

Nickel sulfate Nickel chloride Nickel s'ulfamate Nickel flu'oborate and combinations thereof (3) A leveler selected from the group of Table I. (4) A cooperating compound selected from the group of Table II (optional). (5) A wetting agent (optional).

An additional ingredient of the solution which is desirable is a buffering agent such as boric acid, formic'acid, sodium formate and the like.

It will be noted that in reference to the major constituent of the plating solution the solutions, are similar to the well known all chloride, all sulfate, sulfate-chloride or Watts type, nickel sulfamate and nickel fiuoborate plating solution and combinations thereof. The essential feature of the invention is the use of an acid nickel plating solution having one or more nickel electrolytes and additionally containing one or more cooperating additives, at least one of which is the novel leveling compound of this invention and preferably a cooperating addition agent selected from the compounds of Table II.

In the preparation of the plating solution according to the invention, we add to each of the basic nickel containing solutions a suitable quantity of the leveling compound and preferably one or more of the cooperating compounds. The plating solution for consistent results contains an antipitting agent, although the deposits may be suitable without the antipitting agent. Sodium lauryl sulfate or other wetting agents such as the sodium sulfate derivative of 7-ethyl-2-methyl-undecanol-4 and the dihexyl ester of sodium snlfosuccinic acid may be used as an antipitting agent, although its use is not essential and other mixtures or admixtures of wetting agents may be used to control the pitting.

Specific examples of the electroplating solutions containing dilferent cooperating additives are illustrated in the following table, which has been designated as Table III. It should be understood that the specific electroplating solutions may be employed with or without air agitation.

TABLE III NiSO .6H O ozs./gal 40 NiCl .6H O ozs/gal 6 H BO ozs./gal 5.5 pH 4.0 Temperature F 140 Current density a.s.f to which is added:

g./l Trichloroethanal g./l 0.1

p [2] To the basic solution of Example 1 is added: NH COCH CH OCH :C-CH OCH CH CONH g./l 0.07 Trichloroethanol g./l 0.1

The basic nickel solution of Example l to which is added:

HCECCH (OCH CH CONH g./l 0.03 Tribromoethanal g./l 0.3

To the basic nickel solution of Example 1 is added: NH C0(CH CH O) CH CECCH (OCH C0NH While the foregoing specific electroplating baths are prepared in concentrations and employed at current densities such as will result in the deposition of a semi-bright nickel plate, it should be understood that bright nickel deposits may be obtained by employing appropriate concentrations and current densities. In brief, when a bright nickel deposit is desired, the leveling addition agent should be employed in concentrations from .05 gram per liter to 1.0 gram per liter, while the cooperating'addition agent selected from the group consisting of l,1-diethoxy-2,2,2-trichloroethane, l-hydroxy-l-etl1oxy2,2,2-trichloroethane, l, l-dimethoXy-2,2,2-trichloroethane, l-hydroxy-l-methoxy- 2,2,2-trichloroethane, trichloroethanal and tribromethanal should be employed in concentrations from .05 gram per liter to 0.3 gram per liter.

The leveling addition agent of this invention has been found to be suitable for electrodepositing nic tel upon any of the basis metals commonly employed in the electroplating art, such as, for instance, iron, steel, copper, brass and zinc. It has been found, however, that the leveling addition agent of this invention and particularly when the leveling addition agent of this invention is employed in conjunction with the cooperating addition agent that enhanced nickel electrodeposits are obtained on zinc die castings. The zinc basis metal is, of course, subjected to those pretreatment operation common to the art of electroplating prior to the deposition of nickel from the nickel plating bath of this invention. The coating of zinc basis metal with copper is commonly done prior to electrodeposition of nickel. In general, the degree of leveling obtained through the deposition of a semi-bright plate of this invention is from 20% to 50% for 1 mil deposits. The percentage of leveling is defined as decrease in roughness due to plating initial roughness of basis metal wherein n is an integer from 0 to 1 inclusive, R is a member selected from the group consisting of hydrogen and alkyl having from 1 to 11 carbon atoms, R is a member selected from the group consisting of 0 (OCHzCHfl) r- NHZ and CH 0 t l (OCHQCHZ) w "O OH:- H NHZ wherein y is an integer from 1 to 20, w is an integer from 0 to 20, Z is a member selected from the group consisting of hydrogen, alkyl and hydroxymethyl, and R is a member selected from the group consisting of hydrogen, hydroxymethyl, and alkyl group having from 1 to 11 carbon atoms,

CEC(|3R2 and wherein R and R are the same as previously defined, said leveling additive being present in the range of from .005 gram per liter to 1.0 gram per liter.

2. The nickel plating solution of claim 1 wherein said leveling additive is present in the range of from .005 gram per liter to 0.1 gram per liter.

3. A nickel plating solution comprising an aqueous acid solution of nickel material supplying nickel ions, a leveling additive having the general formula H R3CEC(CH2)n-( JR2 wherein n is an integer from 0 to 1 inclusive, R is a radical selected from the class consisting of hydrogen and an alkyl group having from 1 to 11 carbon atoms, R is a radical selected from the class consisting of wherein y is an integer from 1 to 20, w is an integer from 0 to 20, Z is a radical of the class consisting of hydrogen, alkyl and hydroxymethyl, and R is selected from the class consisting of hydrogen, hydroxymethyl, alkyl having from 1 to 11 carbon atoms,

wherein R and R are the same as previously defined, and at least one cooperating additive selected from the group consisting of 1,1-diethoxy-Z,2,2-trichloroethane, 1- hydroxy-l-ethoxy-2,2,Z-trichloroethane, 1,1-dirnethoxy-2, 2,2-trichloroethane, l-hydroxy-l-methoxy-2,2,Z-trichloroethane, l-hydroxy-1-ethoxy-2,2,2-tribromoethane, 1,1-dimethoxy 2,2,2-tribromoethane, trichloroethanal, and tribromoethanal, said leveling additive being present in the range of from 0.005 gram per liter to 1.0 gram per liter and said cooperating additive being present in the range of from .05 gram per liter to 1.0 gram per liter.

4. The nickel plating solution of claim 3 wherein said cooperating additive is trichloroethanal.

5. The nickel plating solution of claim 3 wherein said 6 leveling agent is present in the range of from .05 gram per liter to 1.0 gram per liter, and said cooperating addi tive is present in the range of from .05 gram per liter to 0.3 gram per liter.

6. A nickel plating solution comprising an aqueous acid solution of nickel material supplying nickel ions and a leveling additive selected from the group consisting of:

HCEC-CH OCH CH CONH NH CO CH CH OCH C E CCH OCH CH CONH NH CO (CH CH O 3CH2CECCH2 (OCH CH CONH Eccn ocn cn corur (1H3 (1H3 NHZO O CHCHzO CHzCEC CH2O CHzCHC ONHz HOCH NHCOCH CH OCH C ECCH OCH CH CONHCH OH CH NHCOCH CH OCH CECCH OCH CH CONHCH and a cooperating additive selected from the group consisting of:

1,1-diethoxy-2,2,Z-trichloroethane l-hydroxy-1-ethoxy-2,2,Z-trichloroethane 1,l-dimethoxy-2,2,2-trichloroethane 1-hydroxy-l-meth0Xy-2,2,2-trichloroethane l-hydroxy-1-ethoXy-2,2,2-tribrom0ethane l,l-dimethoxy-2,2,2-tribromoethane triehloroethanal tribromoethanal said leveling agent being present in the range of from .01 gram per liter to 0.3 gram per liter and said cooperating additive being present in the range of from .01 gram per liter to 2.0 grams per liter.

7. The nickel plating solution of claim 6 wherein said cooperating additive is trichloroethanal.

8. The nickel plating solution of claim 6 wherein said leveling agent is present in the range of from .05 gram per liter to 1.0 gram per liter, and said cooperating additive is present in the range of from .05 gram per liter to 0.3 gram per liter.

9. A method of depositing a semi-bright nickel coating on a metallic object comprising electrolyzing between said metallic object and a nickel anode a nickel plating solution comprising an aqueous acid solution of nickel material supplying nickel ions, a leveling additive having the general formula:

wherein n is an integer from 0 to 1 inclusive, R is chosen from the class consisting of hydrogen and an alkyl group having from 1 to 11 carbon atoms, R is chosen from the class consisting of O 2 H2)y NHZ and H3 O l it (OCHQCH2)W OCHZ H -NHZ wherein y is an integer from 1 to 20, w is an integer from 0 to 20, Z is a radical selected fromthe class consisting of hydrogen, alkyl and hydroxymethyl, and R being chosen from the class consisting of hydrogen, hydroxymethyl, an alkyl group having from 1 to 11 carbon atoms,

wherein R and R are the same as previously defined, and at least one cooperating additive selected from the group consisting of l,1-diethoXy-2,2,2-trichloroethane, l-hy- 7 droxy-l-ethoxy-2,2,2-trichloroethane, 1,1-dimethoxy-2,2, 2 trichloroethane, 1-hydroxy-l-meth0xy2,2,2-trichloroethane, l-hydroxy-1-eth0Xy-2,2,2-tribromoethane, 1,1-dimethoxy-Z,2,2-tribromoethane, trichloroethanal, and tribromoethanal, said leveling additive being present in the range of from .01 gram per liter to 0.3 gram per liter and said cooperating additive being present in the range of from .05 gram per liter to 1.0 gram per liter.

10. The method of claim 9 wherein said cooperating additive is trichloroethanal.

11. The method of claim 9 wherein said leveling additive is present in the range of from .05 gram per liter to g 1.0 gram per liter and wherein said cooperating additive is present in the range of from .05 gram per liter to 0.3 gram per liter.

12. The method of claim 9 wherein said metallic object is a zinc die casting pretreated with a copper coating.

References Cited in the file of this patent UNITED STATES PATENTS 2,900,707 Brown Aug. 25, 1959 FOREIGN PATENTS 1,231,332 France Apr. 11, 1960 UNITED STATES PATENT OFFICE- CERTIFICATE OF CORRECTION Patent No. 3,160,574 December 8, 1964 Jack L. Towle 'et al. 1

Column v3, line 67, for "NH COCH GH OCH C-CH OCH CH CONH read NH COCH CH OCH C C-CH OCH CH CONH line 69, for

Trichloroethanol" read Trichloroethanal column 4, line 4, for "NH CO(CI-I CH O) CH CECCH (OCH CONH read NH CO(CH CH O) CH CECCH (OCH CH CONH lines 41 and 42 for "tribromethanal" read tribromoefhanal columnn5' lines 45 and 46, the formula should appear as shown below instead of as in the patent:

CH O

Jigned and sealed this 13th day of April 1965.,

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J, BRENNER Attesting Officer Commissioner of Patents 

1. A NICKEL PLATING SOLUTION COMPRISING AN AQUEOUS ACID SOLUTION OF NICKEL MATERIAL SUPPLYING NICKEL IONS AND A LEVELING ADDITIVE HAVING THE GENERAL FORMULA: 